In general, the water treatment facilities such as septic tank, sewage treatment facility, waste water treatment facility, and rainwater storage are laid under the ground. Such water treatment facilities are installed in the molds sectioned by the walls into the multiple spaces in the excavated area over which the concretes are deposited and cured. Another installation is to interconnect the blocks that are formed in one type in the factory and delivered to the excavated area. One example is disclosed in the publication of the registered utility model, No. 20-0332793, “Movable concrete module reactor for sewage and waste water treatment facility”.
The structure disclosed in the literature consists of the main body formed in one body with all-around side walls and the bottom plane made of the ferroconcretes, the cover interconnected to the open upper plane of the main body, and at least one of the opening parts penetrated into the side walls. Thus, such structure has the effects of shortening the construction time as well as saving the construction cost for the main body can be readily delivered to the construction site, and can be simply installed with improved durability and safety. Also, such structure allows the main bodies to be combined in a variety of forms in parallel or in series for the treatment of sewage and waste waters.
However, the literature does not disclose the specific solutions as to the control and guide of the water level. Moreover, it has disadvantage that the disclosed structure cannot be used for a variety of water treatments due to the opening parts formed at the specific locations of the main body.